Priscilla C. Veggi

Fundamentals of Microwave Extraction

Microwave-assisted extraction (MAE) is a process that removes solutes from a solid matrix into a solvent. Phenomena such as electromagnetic transfer, heat transfer, mass transfer, and momentum transfer make the process complex. For developing process engineering, the characteristics of heat and mass transfer are extremely significant. Accurate and controlled heat is possible because of the capacity of microwave radiation to penetrate and combine with a substrate. Therefore, the microwave procedure can be designed to transport electromagnetic energy with specific power to the location of the compounds of interest in the substrate. The energy-saving factors and short processing times lead to a reduction in manufacturing costs, and improvement of product uniformity and yields, resulting in products with high quality compared with other extraction techniques. This chapter provides a general review of heat and mass transfer and gives a brief discussion on the factors influencing the extraction efficiency of MAE. The performance of MAE is also compared to other classical methods, thus explaining the advantages of MAE technology as applied to plant extraction research.

Supercritical Fluid Extraction Of Lemon Verbena (Aloysia triphylla): Process Kinetics and Scale-Up, Extract Chemical Composition and Antioxidant Activity, and Economic Evaluation

The extract of lemon verbena ( Aloysia triphylla ) was obtained by supercritical fluid extraction (SFE) using laboratory and pilot scale equipments. The scale-up criterion selected (maintaining solvent to feed ratio constant) was successfully used for a 14-fold scale-up. The extract obtained in pilot scale was separated in three fractions, which were characterized as for their phytochemical profile, total flavonoids content, and antioxidant activity. The extracts obtained by SFE were compared to classical Soxhlet extraction method. Maximum yield obtained for SFE was 1.8%, and for Soxhlet, 7.1%. The chemical composition revealed different phytochemical profiles for SFE and Soxhlet extracts; the last ones presented more flavonoids, while SFE extracts were more concentrated in volatile compounds. The major compounds identified in the volatile fraction of the extracts were spathulenol, phytol and octadecatrienal. Some extracts presented pro-oxidant activity and others presented antioxidant activity. The SFE process was shown to be economically feasible for obtaining lemon verbena extracts; the minimum manufacturing cost (COM) obtained was US

Scale-Up Issues and Cost of Manufacturing Bioactive Compounds by Supercritical Fluid Extraction and Ultrasound Assisted Extraction

1070.00/kg, with a payback time of 2 years.

Optimization and economic evaluation of pressurized liquid extraction of phenolic compounds from jabuticaba skins

Because of the today’s pursuit for healthy products, the production of vegetable extracts by supercritical fluid extraction (SFE) and ultrasound assisted extraction (UAE) is a field of industrial interest. Nonetheless, the lack of information on scale-up of these technologies to the industrial level and the relatively high investment associated with emergent extraction processes is responsible for the elimination of these technologies at the very early stages of process design, that is, during the selection of the extraction process. In order to avoid this prejudice, a preliminary analysis of the cost of manufacturing (COM) should be conducted with a minimum of experimental information, possibly gathered from the literature. If this tool is available to process design engineers, the various extraction techniques can be analyzed without any high investment bias. Thus, a simple method to estimate the COM of extracts by SFE and UAE is needed. In this chapter, rapid methods to estimate the COM of extracts obtained by these techniques are presented. The information required to perform such analysis is discussed based on scale-up issues. A compilation of the published data on the scale-up and COM of SFE and UAE processes is presented.